Oil and gas drilling operations have increased dramatically over the last decade. Each new producing well requires the installation of the casing or pipe comprising many lengths of individual pipes which are threaded to one another as it is added to those in the well bore. As each new length is added and lowered into the hole, another length of pipe must be positioned and threaded to the uppermost pipe in the string.
This operation is a relatively time consuming and expensive process. Prior methods and means have consisted of using a very expensive piece of equipment, referred to as power tongs, or a rather cumbersome technique that utilizes the rotary head of a top head drive drilling rig adapted with a special spindle and a threaded plug.
The power tongs are a special piece of equipment used solely to grip the pipe tube and torque a length of pipe to threadably connect it to the upper most length of pipe in the string already in the hole. The other method using the rotary head of the drilling rig to rotate pipe for makeup or break out requires threading an adapter plug into the pipe coupling member prior to rotating the pipe itself. Then the adapter must be torqued in the opposite direction to release it from the pipe coupling. One of the drawbacks of using such an apparatus is that this technique sometimes causes an inadvertent unthreading in the pipe string which is obviously undesirable.
While it is desirable to be able to employ the existing rotary drive head of the drilling rig rather than require an additional piece of equipment such as power tongs costing approximately twenty to twenty-five thousand dollars, the cumbersome and time consuming process used the the unreliability encountered has forced many users to use the power tongs in spite of the expensive investment.
However, a very serious problem using the expensive power tong device can also be encountered when a pipe coupling has not been threaded fully onto the pipe prior to connecting this pipe into the string. Since the power tong only torques the pipe or tube itself, a loose or hand tight coupling may be unnoticed and may result in the entire string being dropped into the hole. Such occurrences are not rare and represent a very costly accident. Another disadvantage to the use of tongs is that at least two additional workers must be involved. This adds additional expense in the operation and makes a more crowded work place, which is a less safe work condition. Further, since the tong device actually grips the pipe or tube itself, damage to the casing may result.
While many, many years have passed, these problems encountered in running well pipe and casing have not been satisfactorily solved prior to the present invention.